FORECASTING TORNADOES IN GEORGIA

Abstract

Some climatological data on the seasonal, diurnal, and geographical distribution of tornadoes in Georgia are presented, and the tornado ?season? is defined as occurring from February through April. Twelve different storms producing tornadoes during one or more 12-hour forecast periods are studied for synoptic similarities. A mean tornado sounding and a 700-mb. composite chart, taken from data preceding tornado occurrences, are shown. Large differences are found in surface map types whereas at the 700-mb. level there are striking similarities. The synoptic similarities are incorporated into an objective forecast aid through a stratification process such that most ?no-tornado? cases are quickly dismissed by an inspection of the maps currently available in forecast offices, whereas ?threat? cases must be further checked against five criteria and four scatter diagrams. Tests show that this aid, when used as a method in itself, correctly anticipates most of these storms and at the same time, it results in about 2½ forecasts of tornadoes for every one reported.